diff mbox

[v5,6/8] Documentation: bindings: add compatible specific to legacy SCPI protocol

Message ID 1478148731-11712-7-git-send-email-sudeep.holla@arm.com
State New
Headers show

Commit Message

Sudeep Holla Nov. 3, 2016, 4:52 a.m. UTC
This patch adds specific compatible to support legacy SCPI protocol.

Cc: Rob Herring <robh+dt@kernel.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

---
 Documentation/devicetree/bindings/arm/arm,scpi.txt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

-- 
1.9.1

Comments

Olof Johansson Nov. 10, 2016, 7:03 p.m. UTC | #1
On Thu, Nov 10, 2016 at 6:34 AM, Sudeep Holla <sudeep.holla@arm.com> wrote:
>

>

> On 10/11/16 14:12, Rob Herring wrote:

>>

>> On Thu, Nov 10, 2016 at 4:26 AM, Sudeep Holla <sudeep.holla@arm.com>

>> wrote:

>>>

>>>

>>>

>>> On 10/11/16 01:22, Rob Herring wrote:

>>>>

>>>>

>>>> On Wed, Nov 02, 2016 at 10:52:09PM -0600, Sudeep Holla wrote:

>>>>>

>>>>>

>>>>> This patch adds specific compatible to support legacy SCPI protocol.

>>>>>

>>>>> Cc: Rob Herring <robh+dt@kernel.org>

>>>>> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

>>>>> ---

>>>>>  Documentation/devicetree/bindings/arm/arm,scpi.txt | 4 +++-

>>>>>  1 file changed, 3 insertions(+), 1 deletion(-)

>>>>>

>>>>> diff --git a/Documentation/devicetree/bindings/arm/arm,scpi.txt

>>>>> b/Documentation/devicetree/bindings/arm/arm,scpi.txt

>>>>> index d1882c4540d0..ebd03fc93135 100644

>>>>> --- a/Documentation/devicetree/bindings/arm/arm,scpi.txt

>>>>> +++ b/Documentation/devicetree/bindings/arm/arm,scpi.txt

>>>>> @@ -7,7 +7,9 @@ by Linux to initiate various system control and power

>>>>> operations.

>>>>>

>>>>>  Required properties:

>>>>>

>>>>> -- compatible : should be "arm,scpi"

>>>>> +- compatible : should be

>>>>> +       * "arm,scpi" : For implementations complying to SCPI v1.0 or

>>>>> above

>>>>> +       * "arm,legacy-scpi" : For implementations complying pre SCPI

>>>>> v1.0

>>>>

>>>>

>>>>

>>>> I'd prefer that we explicitly enumerate the old versions. Are there

>>>> many?

>>>>

>>>

>>> I understand your concern, but this legacy SCPI protocol was not

>>> officially released. It was just WIP which vendors picked up from very

>>> early releases. Since they are not numbered, it's hard to have specific

>>> compatibles with different versions until v1.0. That's one of the reason

>>> to retain platform specific compatible so that we can add any quirks

>>> based on them if needed.

>>>

>>> I will probably add these information in the commit log so that it's

>>> clear why we can't do version based compatible.

>>

>>

>> This is exactly my point. By enumerate, I meant having platform

>> specific compatibles. Having "arm,legacy-scpi" is pointless because

>> who knows what version they followed and they may all be different.

>>

>

> OK, but IIUC Olof's concern wanted a generic one along with the platform

> specific compatible which kind of makes sense as so far we have seen

> some commonality between Amlogic and Rockchip.

>

> E.g. Amlogic follows most of the legacy protocol though it deviates in

> couple of things which we can handle with platform specific compatible

> (in the following patch in the series). When another user(Rockchip ?)

> make use of this legacy protocol, we can start using those platform

> specific compatible for deviations only.

>

> Is that not acceptable ?


If there's no shared legacy feature set, then it's probably less
useful to have a shared less precise compatible value.

What the main point I was trying to get across was that we shouldn't
expand the generic binding with per-vendor compatible fields, instead
we should have those as extensions on the side.

I'm also a little apprehensive of using "legacy", it goes in the same
bucket as "misc". At some point 1.0 will be legacy too, etc.


-Olof
diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/arm/arm,scpi.txt b/Documentation/devicetree/bindings/arm/arm,scpi.txt
index d1882c4540d0..ebd03fc93135 100644
--- a/Documentation/devicetree/bindings/arm/arm,scpi.txt
+++ b/Documentation/devicetree/bindings/arm/arm,scpi.txt
@@ -7,7 +7,9 @@  by Linux to initiate various system control and power operations.
 
 Required properties:
 
-- compatible : should be "arm,scpi"
+- compatible : should be
+	* "arm,scpi" : For implementations complying to SCPI v1.0 or above
+	* "arm,legacy-scpi" : For implementations complying pre SCPI v1.0
 - mboxes: List of phandle and mailbox channel specifiers
 	  All the channels reserved by remote SCP firmware for use by
 	  SCPI message protocol should be specified in any order